'86 420 SEL Chain Install Tool - PeachParts Mercedes-Benz Forum

Randy · #1 03-23-2006, 09:59 PM

Anyone ever use one of those tools which hold the chain on the right-side sprocket while you are barring it through? Does it work OK? Does anyone have one they want to sell? Thanks.

Q · #2 03-23-2006, 10:33 PM

I used one called zip-ties. Worked really well and cheap too. Of course, it was a REALLY slow process.

Randy · #3 03-23-2006, 10:43 PM

I understand; right now cheap would help a lot: I priced the OEM tensioner OUCH. Why the heck can't the aftermarket ones be as good?
I am interested: how much force does it take to hold the chain ends on? I hate to disturb the rockers (and I hate to buy a spring compressor, too). Dang, the first time is tough (hope it's the last time, too).

Tomguy · #4 03-23-2006, 11:11 PM

Did you read my DIY article on timing chain replacement?

http://www.peachparts.com/Wikka/M117TimingChain

The m116's chain is a bit shorter, which means the process will take less time on a 4.2 than it did on my 4.5. It's easy to do, the mini vicegrips I used were like $0.99 each at Wal*Mart. Your guide rails will be plastic though, you WILL want to replace them.

Strife · #5 03-24-2006, 12:11 AM

I have one, and I used it. It worked very well, and makes the grinding off of the pins much safer, because you don't have to worry about the ends flying off after you do it. Not being a mechanic, I didn't want to take any chances dropping the chain or skipping it, and this looked like good insurance. My assistant (wife) has even less experience working on engines. She fed the chain while I turned the crank (supposedly, this cover makes this a one-man operation, but I didn't want to drag the chain(s) on the fender).

Nonetheless, I did manage to do two idiotic things in the process:

1. I had (clean, lint-free) rags stuffed down the sides near the chain in the event I dropped something in. One of the rags got caught in the chain between it and the cover. I couldn't turn the gear backwards so I had to cut it out with a razor blade before proceeding.

2. The cover bolts on top of the front cam tower. When I removed the cover, I didn't torque the bolts to spec, and I turned the engine over by hand with the lifters reinstalled (NOT GOOD). Fortunately, I didn't do this at any speed, and after removing the lifters, torquing the front cam tower, and checking that the cam turned without any binding or tough spots (meaning, I bent the cam), I reinstalled everything and then TORQUED THE FRONT CAM TOWER BOLTS for the last time, ever, hopefully!

Strife · #6 03-24-2006, 12:23 AM

On removing the cam followers, once you have the tool, it's very easy. There was some debate on another board on whether or not this can be done safely if left in AND the tensioner left in also. Obviously, it can be done, because people have done it. So, why do MB and Haynes, Chilton recommend removing them? I think it's for two reasons:

1. Unexpected movement of the chain/gear due to spring action

2. If you remove the tensioner (which is recommended in the books), the RH side of the chain has a lot of slop in it, certainly more than a tooth's worth, and certainly more than enough to cause interference. Having the tensioner in makes the job a little more difficult; If your tensioner is older, it probably leaks a little, the spring is old, is it really going to hold enough tension? I did not feel like gambling $2000 to find out (note that the LH side is always under tension during the process and unless something really gross happens, you can't skip a tooth on that side).

My 0.02: Unless you are a seasoned mechanic (I'm not) or just plain born lucky (I'm not), I'd go by the book. But I think the vise-grips are a neat idea.